Hi
This is the official patch to implement TCP Hybla congestion avoidance.

- "In heterogeneous networks, TCP connections that incorporate a 
terrestrial or satellite radio link are greatly disadvantaged with 
respect to entirely wired connections, because of their longer round 
trip times (RTTs). To cope with this problem, a new TCP proposal, the 
TCP Hybla, is presented and discussed in the paper[1]. It stems from an 
analytical evaluation of the congestion window dynamics in the TCP 
standard versions (Tahoe, Reno, NewReno), which suggests the necessary 
modifications to remove the performance dependence on RTT.[...]"[1]

[1]: Carlo Caini, Rosario Firrincieli, "TCP Hybla: a TCP enhancement for 
heterogeneous networks", 
International Journal of Satellite Communications and Networking
Volume 22, Issue 5 , Pages 547 - 566. September 2004.

Please note that this patch:
- cleanly compiled against 2.6.11-rc4;

- reached very good results in terms of fairness and friendliness with 
other TCP standards and proposals during tests;

- gives a throughput very close to maximum fair share when satellite 
connections fight for bandwidth in a terrestrial bottleneck, and 
improves their performance also in case of no congestion;

- acts exactly as newreno when minimum rtt estimated by the sender is 
lower or equal to rtt0 (default=25 ms).

The protocol is obviously disabled by default and can be turned on by 
switching its sysctl, as usual.
As Mr.Yee-Ting Li pointed out in his last thread, the deployments of 
these experimental protocols are too premature and they should be 
switched OFF by default to prevent undesirable consequences to network 
stability.

One last note: IMHO we really need a better way to select congestion 
avoidance scheme between those available, instead of switching each one 
on and off. I.e., we can't say how vegas and westwood perform when 
switched on together, can we?

I'd really appreciate if you consider my work for apply.
TIA,

-- 
Daniele Lacamera
root at danielinux.net